According to medical sources, at least 10 people of the Haniyeh family were killed in an Israeli air attack against their home in the Beach refugee camp, western Gaza City.
On April 10, Haniyeh lost three of his sons in an Israeli airstrike on their car in the Beach camp.
Israel, flouting a United Nations Security Council resolution demanding an immediate cease-fire, has faced international condemnation amid its continued brutal offensive on Gaza since an Oct. 7 attack last year by Hamas.
More than 37,600 Palestinians have since been killed in Gaza, most of them women and children, and nearly 86,100 others injured, according to local health authorities.
More than eight months into the Israeli war, vast tracts of Gaza lie in ruins amid a crippling blockade of food, clean water, and medicine.
Israel is accused of genocide at the International Court of Justice, whose latest ruling ordered it to immediately halt its operation in the southern city of Rafah, where more than 1 million Palestinians had sought refuge from the war before it was invaded in early May.